Systems and methods for thermal management in utility scale power inverters

ABSTRACT

A power electronics system comprising a environmentally sealed electronics compartment for housing power electronics equipment is provided. The system includes a plenum within the sealed electronic compartment for circulating air. A first liquid cooling loop is configured to cool air flowing through the plenum. A second liquid cooling loop configured to directly cool the power electronics equipment. The system includes a controller configured to independently control the flow rate of the first liquid cooling loop and the second liquid cooling loop.

RELATED APPLICATIONS

This application is a U.S. National Stage Application under 35 U.S.C. §371 of International Application No. PCT/US2017/038104, filed Jun. 19,2017, titled SYSTEMS AND METHODS FOR THERMAL MANAGEMENT IN UTILITY SCALEPOWER INVERTERS, which claims the benefit under 35 U.S.C. § 119(e) ofU.S. Provisional Application No. 62/352,431, filed Jun. 20, 2016, titledSYSTEMS AND METHODS FOR THERMAL MANAGEMENT IN UTILITY SCALE POWERINVERTERS, both of which are hereby incorporated by reference in theirentirety for all purposes.

This application relates to U.S. Patent Application Ser. No. 62/352,406,filed Jun. 20, 2016, titled SYSTEMS AND METHODS FOR HUMIDITY CONTROL INUTILITY SCALE POWER INVERTERS, which is incorporated by reference in itsentirety for all purposes.

BACKGROUND Field of Invention

Embodiments of the present invention relate generally to utility scalepower inverter's enclosures.

Discussion of Related Art

A power inverter, or inverter, is an electronic device or circuitry thatconverts direct current (DC) to alternating current (AC). Inverters maybe used in a number of different contexts, with different DC powersources (such as lead acid batteries, photovoltaic solar panels, windturbines, etc.), and may be designed to satisfy different power demandsof a system.

Utility scale solar inverters, in particular, convert variable DC outputof a photovoltaic (PV) solar panel into a utility frequency AC toprovide power to either a commercial electrical grid or a local,off-grid electrical network. Solar inverters are connected to aplurality of photovoltaic cells that provide DC input to the inverter.The inverter comprises at least one DC-to-AC power conversion bridge,associated filter electronics and an AC (output) module. The DC-to-ACpower conversion bridge uses a plurality of electronic switches,typically insulated gate bipolar transistors (IGBTs), and diodes toconvert the DC input into AC output. For grid-connected invertersproviding power to an electricity grid, the AC output is filtered toprovide an AC output waveform that is suitable for the grid.Furthermore, solar power inverters have special functions adapted foruse with photovoltaic arrays, including maximum power point tracking andanti-islanding protection.

During operation, various components of a solar inverter (including thepower conversion bridges and filter electronics/magnetics) generatesignificant heat and typically require cooling. For low power solarinverters, providing cooling airflow around heat-producing components ofthe inverter module is often sufficient. Air-cooling (using fans,blowers, radiators etc.) has also been used for thermal management inconventional high power (>1 MW) solar inverters where the enclosure isvented (open to the surroundings). However, high power solar invertersgenerally require more sophisticated cooling, and are sometimesliquid-cooled. Additionally, the power density requirements for solarinverters have continued to increase such that traditional air-coolingis not well suited to the heat extraction requirements.

The liquid coolant loop in high power solar inverters is sometimes partof a larger cooling system used for other purposes. For high power solarinverters, such an approach can be inadequate to reliably remove theheat generated. Moreover, the integration of a solar inverter into alarger multi-system cooling system on-site is a skilled task and makesthe installation and maintenance of such solar inverters expensive.

Some approaches have described a liquid-cooled solar inverter in whichliquid coolant is pumped around elements of the solar inverter, in asingle loop, in order to cool elements of the DC module, the invertermodule, and/or the AC module. The liquid coolant may be directed to aheat exchanger in which the liquid coolant is air cooled.

Solar inverters need to be able to operate in harsh environments (sandy,dusty, hot, cold, sea-side, varied weather conditions etc.) and have along lifetime requirement (e.g., 30 years) with high uptimerequirements. The thermal management system is preferably robust andreliable and in order to thermally regulate and protect the expensiveand complex equipment in the solar inverter. Furthermore, the thermalmanagement system is preferably compact, efficient to operate and ispreferably easy to install and maintain.

SUMMARY

In at least one embodiment in accordance with principles of the presentinvention, a power electronics system comprising an environmentallysealed electronics compartment for housing power equipment is provided.The system includes a plenum within the sealed electronic compartmentfor circulating air. A first liquid cooling loop is configured to coolair flowing through the plenum. A second liquid cooling loop configuredto directly cool the power electronics equipment. The system includes acontroller configured to independently control the airflow rates and thecoolant flow rates of the first liquid cooling loop and the secondliquid cooling loop.

The power electronics equipment of the system may include an inverter.The internal environmental sensor and the external environmental sensormay be temperature sensors for obtaining temperature information withinthe sealed electronics compartment and outside the compartment,respectively. In some embodiments, the first liquid cooling loopincludes a plurality of heat exchangers and a fan for circulating airthrough the plenum. In addition, the second liquid cooling loop mayinclude a thermal plate. In other embodiments, the controller may beprogrammed to analyze environmental data to control the flow rate of theliquid cooling loops and the airflow to maintain a pre-set temperaturewithin the sealed electronics compartment.

One aspect of the disclosure is directed to a power electronics systemcomprising an environmentally sealed electronics compartment for housingpower electronics equipment, a plenum within the sealed electronicscompartment for circulating air, a first liquid cooling loop configuredto cool air flowing through the plenum, a second liquid cooling loopconfigured to directly cool the power electronics equipment, and acontroller for independently controlling airflow rates and coolant flowrates of the first liquid cooling loop and the second liquid coolingloop.

Embodiments of the system further may include the power electronicsequipment embodying an inverter. The power electronics equipment mayinclude an inverter. The first liquid cooling loop may include aplurality of heat exchangers and at least one fan for circulating airthrough the plenum. The controller may be programmed to analyzeenvironmental data to control air and coolant flow rates of the firstand second liquid cooling loops to maintain a pre-set temperature withinthe sealed electronics compartment. The first liquid cooling loop mayinclude a first heat exchanger, a second heat exchanger, and a pump tocirculate a liquid coolant in the first liquid cooling loop. The systemfurther may include a fan to circulate air within the sealed electronicscompartment, the fan being configured to draw air through the duct andblowing air through the first heat exchanger. The system further mayinclude at least one fan to draw air from outside across the second heatexchanger to reduce a temperature of liquid coolant passing through thesecond heat exchanger. The first liquid cooling loop may include a firstheat exchanger and the second liquid cooling loop may include a secondheat exchanger, the system further comprising at least one fanconfigured to draw air across the first heat exchanger and the secondheat exchanger. The plenum may be configured to direct air across anupper portion or ceiling of the sealed electronics compartment and downan interior side wall of the sealed electronics compartment. The secondliquid cooling loop may include a heat exchanger and a pump to circulateliquid coolant in the second liquid cooling loop. The second liquidcooling loop may be configured to direct coolant through the powerelectronics equipment or through a device associated with the powerelectronics equipment. Coolant in the second liquid cooling loop may beconfigured to flow through channels inside a thermal plate to which apower conversion bridge is mounted. Coolant in the second liquid coolingloop further may be configured to flow through multiple thermal platesin contact with filter electronics and associated magnetic components.Coolant in the second liquid cooling loop may be configured to flowadjacent to or with electronic switches. The controller may beconfigured to receive environmental data from environmental sensors tocontrol the operation the first liquid cooling loop and the secondliquid cooling loop.

Another aspect of the disclosure is directed to a method of thermalcontrol in a power electronics system. In one embodiment, the methodcomprises: controlling the flow rate of a first liquid cooling loopwithin a plenum of a sealed electronics compartment for housing powerelectronics equipment; and controlling the flow rate of a second liquidcooling loop configured to directly cool the power electronics equipmentwithin the sealed electronics compartment.

Embodiments of the method further may include circulating air through aplenum provided within the sealed electronics compartment. The methodfurther may include circulating air through a plenum provided within thesealed electronics compartment. The method further may includecirculating air within the sealed electronics compartment, drawing airthrough the plenum, and blowing air through a heat exchanger. The firstliquid cooling loop may include a plurality of heat exchangers and atleast one fan for circulating air through the plenum. The method furthermay include drawing air from outside the sealed electronics compartment,and directing air across a heat exchanger to reduce a temperature ofliquid coolant passing through the heat exchanger. The method furthermay include analyzing environmental data, and controlling flow rates ofthe first and second liquid cooling loops to maintain a pre-settemperature within the sealed electronics compartment. The second liquidcooling loop may be configured to direct coolant through the powerelectronics equipment or through a device associated with the powerelectronics equipment. Coolant in the second liquid cooling loop may beconfigured to flow through channels inside a thermal plate to which apower conversion bridge is mounted. Coolant in the second liquid coolingloop further may be configured to flow through multiple thermal platesin contact with filter electronics and associated magnetic components.Coolant in the second liquid cooling loop may be configured to flowadjacent to or with electronic switches.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are not intended to be drawn to scale. In thedrawings, each identical or nearly identical component that isillustrated in various figures is represented by a like numeral. Forpurposes of clarity, not every component may be labeled in everydrawing. In the drawings:

FIG. 1 is a schematic diagram of a power equipment enclosure with acooling system in accordance with principles of the invention;

FIG. 2A is an isometric view of an embodiment of a portion of a dualloop liquid cooling system in accordance with principles of theinvention;

FIG. 2B is a second isometric view of an embodiment of a portion of adual loop liquid cooling system in accordance with principles of theinvention;

FIG. 3 is an isometric view of an embodiment of a thermal plate that maybe used in accordance with principles of the invention;

FIG. 4 is a front view of an inverter enclosure in accordance withprinciples of the invention;

FIG. 5 is a rear view of an inverter enclosure in accordance withprinciples of the invention;

FIG. 6 is a right side view of an inverter enclosure in accordance withprinciples of the invention;

FIG. 7 is a left side view of an inverter enclosure in accordance withprinciples of the invention;

FIG. 8 is a front/topside isometric view of an inverter enclosure inaccordance with principles of the invention;

FIG. 9 is a rear/topside isometric view of an inverter enclosure inaccordance with principles of the invention;

FIG. 10 is a front/topside interior isometric view of an inverterenclosure in accordance with principles of the invention;

FIG. 11 is a rear/topside interior isometric view of an inverterenclosure in accordance with principles of the invention;

FIG. 12 is a schematic diagram of a controller used in connection withembodiments of the invention; and

FIG. 13 is a storage system used in connection with FIG. 12.

DETAILED DESCRIPTION

Unlike in conventional inverters, embodiments of the present inventioninclude a substantially sealed compartment within the utility scaleinverter enclosure that houses the electronics (e.g., power conversionbridge and filter electronics etc.). The sealed compartment is designedto block contaminants such as particulates, and prevent ingress ofliquid water.

To maintain the sealed compartment, as well as meet to the power densityrequirements, a liquid cooling system is used to maintain the electroniccomponents, circuitry and air temperature within the sealed compartmentwithin a desired temperature range.

FIG. 1 shows a simplified schematic diagram of a solar inverter system100 comprising a dual-loop liquid cooling system. Solar inverter system100 comprises sealed electronics compartment 110, which houses variouscomponents that generate heat during operation of the solar inverter,including DC-to-AC power conversion bridge(s) 115 and filter electronics120. Solar inverter system 100 further comprises vented cooling cabinet125, which houses various components of the liquid cooling system. Theliquid coolant is a glycol-based coolant (ethylene glycol), althoughother suitable liquid coolants can be used.

The cooling system includes two heat exchange loops 130 and 150. Firstheat exchange loop 130 cools the air within sealed electronicscompartment 110, and comprises two heat exchangers 132 and 136, and apump 134 for circulating a liquid coolant in first heat exchange loop130. A fan 138 circulates air within sealed electronics compartment 110,drawing it through a duct 160 formed within compartment 110 and blowingit through air to liquid heat exchanger 132 (airflow within thecompartment is indicated by the black arrows), so that heat istransferred to the liquid coolant in loop 130 via heat exchanger 132.Duct 160, which may be referred to as a plenum, directs the airflowacross the upper portion or ceiling of compartment 110 and down oneinterior side wall of the compartment. Liquid coolant in loop 130 isthen directed through liquid to air heat exchanger 136, which is mountedin an external wall of cooling cabinet 125. Air from outside is drawnthrough heat exchanger 136 by a pair of fans 140 a and 140 b (asindicated by the shaded arrow) and reduces the temperature of liquidcoolant passing through heat exchanger 136. The first heat exchange loop130 is configured to have relatively low grade heat, which is thetemperature differential between coolant in the first heat exchange loop130 and ambient air, e.g., 60° C. for coolant and 50° C. for ambientair.

Second loop 150 directly cools power electronics and magnetic components(including DC-to-AC power conversion bridge(s) 115 and filterelectronics 120) inside sealed cabinet 110. Second loop 150 comprises apump 154 for circulating a liquid coolant in second heat exchange loop150, and a liquid to air heat exchanger 156. Coolant in loop 150 isdirected though one or more serpentine channels inside a thermal plateto which each phase of DC to AC power conversion bridge 115 is mounted,and then through multiple thermal plates (in parallel) which are incontact with filter electronics 120 and associated magnetic components.Heat is transferred from components 115 and 120 (and optionally fromother heat generating components in compartment 110) to the liquidcoolant in loop 150, which is then directed through liquid to air heatexchanger 156. Air from outside is also drawn through heat exchanger 156by fans 140 a and 140 b (as indicated by the shaded arrow) and reducesthe temperature of liquid coolant passing through heat exchanger 156.The second heat exchange loop 150 is configured to have relatively highgrade heat, which is the temperature differential between coolant in thefirst heat exchange loop 150 and ambient air, e.g., 80° C. for coolantand 50° C. for ambient air.

Controller 145 receives environmental data from environmental sensors(not shown here) to control the operation of fans 140 a and 140 b, aswell as pump 134 and pump 154 to regulate the temperature in the system.The controller 145 may also be configured to control the operation ofthe electronic devices within the cabinet 110. The controller isconfigured to independently control airflow rates and coolant flow ratesof the first liquid cooling loop 130 and the second liquid cooling loop150.

Coolant loops 130 and 150 are fluidly connected to coolant reservoirs139 and 159, respectively. Sealed liquid pass-throughs into theelectronics compartment 110 are used. A pair of heaters 170 a and 170 bare positioned in duct 160, and are used primarily to raise thetemperature inside compartment 110 during start-up of solar invertersystem 100 (for example, to mitigate the risk of condensationoccurring).

The temperature of the power electronics (and the associated heatrejection requirement) is typically much higher than for the aircirculating in compartment 110. In other words cooling loop 150 willtend to run hotter (and have a higher temperature differential or “deltaT” relative to the outside temperature) than cooling loop 130. Thehigher the delta T, the more heat that can be rejected for the same heatexchanger setup and size (q=h·ΔT).

In some implementations, coolant loop 150 (for the power electronics)reaches temperatures exceeding 75° C., whereas loop 130 (for the air incompartment 110) reaches temperatures of only around 60° C.

The utilization of two separate cooling loops—one to cool the air in theelectronics compartment, and the other to cool the powerelectronics/magnetics—enables cost efficient and energy efficientcooling in the solar inverter system, and provides excellent thermalmanagement of the power electronics. The coolant flow rate can bedifferent in the two loops, to provide independent control of the deltaTs.

External heat exchangers 136 and 156 are preferably arranged in astacked configuration and share the same pair of fans 140 a and 140 b,as shown in FIG. 1. This essentially doubles the airflow through theheat exchangers (relative to having one fan for each heat exchanger) andenhances the performance/cost trade-off. Because cooling loop 130 isrunning at a lower temperature, heat exchanger 136 is positioned so thatincoming cooling air passes through it first, and then through heatexchanger 156 which is stacked behind it. This configuration increasesor maximizes the delta T for loop 130, and still provides a satisfactorydelta T for cooling loop 150 at heat exchanger 156.

FIGS. 2A and 2B are two different isometric views of an embodiment aportion of a dual-loop liquid cooling system for installation in a solarinverter system. The same reference numerals as were used in FIG. 1 areused in FIGS. 2A and 2B to identify like components.

First cooling loop 130 is connected to coolant pump 134, and to heatexchanger 132, for cooling air that is circulated in a sealedelectronics compartment by fan 138. Coolant in cooling loop 130 is alsodirected through heat exchanger 136 where it is cooled by external airdrawn though heat exchanger 136 by fans 140 a and 140 b. Second coolingloop 150 is connected to coolant pump 154. Coolant pump 154 directscoolant in a parallel through six thermal plates (such as shown in FIG.3). Each thermal plate can be used to cool one phase of a powerconversion bridge. Each thermal plate is fluidly connected to coolantloop 150 at an inlet pipe 150 a and an outlet pipe 150 b. Coolant isthen directed in parallel through multiple thermal plates (not shown inFIGS. 2A and 2B) for cooling AC filter electronics (not shown in FIGS.2A and 2B) via inlet and outlet connections 150 c and 150 d,respectively in loop 150. The coolant is directed through heat exchanger156, which is stacked between heat exchanger 136 and fans 140 a and 140b. Coolant in loop 150 is cooled by external air that is drawn thoughheat exchanger 156 by fans 140 a and 140 b (after passing through heatexchanger 136).

FIG. 3 is an isometric view of an embodiment of a thermal plate 300which can be fluidly connected to coolant loop inlet pipe 150 a (ofFIGS. 2A and 2B) at inlet port 350 a and to coolant loop outlet pipe 150b (of FIGS. 2A and 2B) at outlet port 350 b. Thermal plate 300 ispreferably made of aluminum, although other suitable thermallyconductive materials could be used. Each phase of one or more DC-to-ACpower conversion bridges (for example, comprising insulated gate bipolartransistors (IGBTs), and diodes) can be mounted directly to a thermalplate. Thermal plate 300 comprises internal flow channels through whichthe coolant is directed. For example, one or more serpentine channelscan be used. The channels can be configured and/or the electronichardware can be mounted on thermal plate 300 such that cooling istargeted in the regions where it is needed the most.

In other embodiments, the second liquid cooling loop 150 is configuredto direct coolant directly through the power electronics equipment.

FIGS. 4-9 show various views of a 2 MW solar inverter enclosure 400 intowhich the cooling system shown in FIGS. 2A and 2B can be installed.Enclosure 400 has several access panels or doors allowing access toseparate compartments which house different sub-systems within enclosure400. Like numerals are used to indicate the same or similar componentsthroughout the different views shown in FIGS. 4-9. Solar inverterenclosure 400 can be constructed of aluminum, for goodcorrosion-resistance. The enclosure can be constructed by assembling anumber of separate panels, with gaskets and bolted connections therebetween.

FIG. 4 is a front view of solar inverter enclosure 400, showing ventedroof panel assembly 405, cooling cabinet access panel 410, DC cablingcompartment access panel 420, and electronics compartment access panels430 and 440. FIG. 5 is a rear view of solar inverter enclosure 400,showing vented roof panel 505, vented cooling cabinet access panel 510,and electronics compartment access panels 530 and 540. FIG. 6 is aright-side view of solar inverter enclosure 400, showing communicationcompartment access panel 650, communication wiring compartment accesspanel 660, and display cover/laptop tray 670. FIG. 7 is a left-side viewof solar inverter enclosure 400, showing vented cooling cabinet end wall710.

FIGS. 8 and 9 are front/topside and rear/topside isometric views ofsolar inverter enclosure 400, showing the various access panels asdescribed above. Coolant reservoir access hatch 880 is visible in FIGS.8 and 9.

The same reference numerals as were used in FIG. 1 and FIGS. 2A and 2Bare used to identify like components in FIGS. 10-11.

FIG. 10 is a rear/topside isometric view of solar inverter enclosure 400with the access panels removed to reveal various interior compartmentsthat house different sub-systems within enclosure 400. FIG. 10 showscooling cabinet 125 separated from electronics compartment 110 byinterior panel 1015 which forms part of the internal duct (160 inFIG. 1) through which air is circulated in compartment 110 by fan 138(shown in FIGS. 1, 2A and 2B). Opening 1025 accommodates a heatexchanger (such as heat exchanger 132 of FIGS. 1, 2A and 2B).Communication and auxiliary power compartment 1050 is separated fromelectronics compartment 110 by interior panel 1025. Communication wiringcompartment 1060, and display box 1070 are shown and are defined byinterior panels (not labelled).

FIG. 11 is a front/underside isometric view of solar inverter enclosure400, also with the access panels removed to reveal various interiorcompartments, 110, 1010, 1050 and 1060 as described in reference to FIG.10 above. FIG. 11 also shows DC cabling compartment 1120, which isseparated from electronics compartment 1030 by interior panel 1115, andthe cooling cabinet 125, which is separated from the sealed electronicscompartment 110 and the compartment 1120 by interior panel 715.

In the assembled solar inverter product, electronics compartment 110 issubstantially sealed to prevent ingress of water or dust into thiscompartment—it is rated NEMA Type 4 or IP65. Seals are used around theaccess panels to this compartment. Cooling cabinet 125 is vented or“open-to-environment”, and houses most of the cooling system shown inFIGS. 1, 2A and 2B (including stacked heat exchangers 136 and 156, pumps134 and 154, fans 140 a and 140 b). Sealed liquid pass-throughs into theelectronics compartment 110 are used. This allows much of the liquidcooling system to be located outside electronics compartment 110. DCcabling compartment 1120 has sealed high power bus pass-throughs intosealed electronics compartment 110. This allows DC field wiring to becompleted without exposing the sealed electronics compartment to theenvironment during installation.

Communication and auxiliary power compartment 1050 and communicationwiring compartment 1060 will be accessed more frequently by theoperator, and therefore these components are separated from sealedelectronics compartment 110. Communications and low voltage connectionsenter the solar inverter system via these sections, so that the mainelectronics compartment 110 is not exposed during installation,commissioning or some service operations.

Seven protective screw-in passive vents (Gore Polyvent XL devices), suchas shown at 1080, are installed in the wall panels that defineelectronics compartment 110 as shown in FIGS. 10 and 11. These ventsconsist of a passive water vapor transport membrane and provide passivepressure equalization and humidity control within the compartment 110,as described above.

Various temperature sensors and other sensors are used by a controlsystem to control operation of the thermal management system, includingoperation of pumps and fans (not shown in here). In some embodiments thedual-loop thermal management system is operated to maintain the airtemperature within the electronics compartment at a certain temperature(e.g., 50° C.) or within a certain temperature range during operation ofthe solar inverter system; and, if the cooling system is unable tomaintain the air temperature within the electronics compartment below afirst threshold (say 50° C.), the controller 145 may limit (de-rate) thepower output of the inverter to reduce the amount of heat beinggenerated in order to try to maintain the temperature below the firstthreshold. If the air temperature within the electronics compartmentexceeds a second threshold (the same or higher than the first threshold)the controller 145 may shut down the solar inverter.

Controller 145 of the inverter system 900 may include, for example, ageneral-purpose computer such as those based on Intel PENTIUM-typeprocessor, Motorola PowerPC, Sun UltraSPARC, Hewlett-Packard PA-RISCprocessors, or any other type of processor.

For example, the methods employed in the controller in variousembodiments of the invention may be implemented as specialized softwareexecuting in a general-purpose computer system 1600 such as that shownin FIG. 12. The system 1600 may include a processor 1620 connected toone or more memory devices 1630, such as a disk drive, memory, or otherdevice for storing data. Memory 1630 is typically used for storingprograms and data during operation of the system 1600. The system 1600may also include a storage system 1650 that provides additional storagecapacity. Components of system 1600 may be coupled by an interconnectionmechanism 1640, which may include one or more busses (e.g., betweencomponents that are integrated within the same machine) and/or a network(e.g., between components that reside on separate discrete machines).The interconnection mechanism 1640 enables communications (e.g., data,instructions) to be exchanged between system components of system 1600.

System 1600 also includes one or more input devices 1610, for example, akeyboard, mouse, trackball, microphone, touch screen, and one or moreoutput devices 1660, for example, a printing device, display screen,speaker. In addition, computer system 1600 may contain one or moreinterfaces (not shown) that connect system 1600 to a communicationnetwork (in addition or as an alternative to the interconnectionmechanism 1640).

The storage system 1650, shown in greater detail in FIG. 13, typicallyincludes a computer readable and writeable nonvolatile recording medium1700 in which signals are stored that define a program to be executed bythe processor or information stored on or in the medium 1700 to beprocessed by the program to perform one or more functions associatedwith embodiments described herein. The medium may, for example, be adisk or flash memory. Typically, in operation, the processor causes datato be read from the nonvolatile recording medium 1700 into anothermemory 1710 that allows for faster access to the information by theprocessor than does the medium 1700. This memory 1710 is typically avolatile, random access memory such as a dynamic random access memory(DRAM) or static memory (SRAM). It may be located in storage system1706, as shown, or in memory system 1630. The processor 1620 generallymanipulates the data within the integrated circuit memory 1630, 1710 andthen copies the data to the medium 1700 after processing is completed. Avariety of mechanisms are known for managing data movement between themedium 1700 and the integrated circuit memory element 1630, 1710, andthe invention is not limited thereto. The invention is not limited to aparticular memory system 1630 or storage system 1650.

The computer system may include specially-programmed, special-purposehardware, for example, an application-specific integrated circuit(ASIC). Aspects of the invention may be implemented in software,hardware or firmware, or any combination thereof. Further, such methods,acts, systems, system elements and components thereof may be implementedas part of the computer system described above or as an independentcomponent.

Although computer system 1600 is shown by way of example as one type ofcomputer system upon which various aspects of the invention may bepracticed, it should be appreciated that aspects of the invention arenot limited to being implemented on the computer system as shown in FIG.5. Various aspects of the invention may be practiced on one or morecomputers having a different architecture or components shown in FIG. 5.Further, where functions or processes of embodiments of the inventionare described herein (or in the claims) as being performed on aprocessor or controller, such description is intended to include systemsthat use more than one processor or controller to perform the functions.

Computer system 1600 may be a general-purpose computer system that isprogrammable using a high-level computer programming language. Computersystem 1600 may be also implemented using specially programmed, specialpurpose hardware. In computer system 1600, processor 1620 is typically acommercially available processor such as the well-known Pentium classprocessor available from the Intel Corporation. Many other processorsare available. Such a processor usually executes an operating systemwhich may be, for example, the Windows 95, Windows 98, Windows NT,Windows 2000 (Windows ME) or Windows XP or Vista operating systemsavailable from the Microsoft Corporation, MAC OS System X operatingsystem available from Apple Computer, the Solaris operating systemavailable from Sun Microsystems, or UNIX operating systems availablefrom various sources. Many other operating systems may be used.

The processor and operating system together define a computer platformfor which application programs in high-level programming languages arewritten. It should be understood that embodiments of the invention arenot limited to a particular computer system platform, processor,operating system, or network. In addition, it should be apparent tothose skilled in the art that the present invention is not limited to aspecific programming language or computer system. Further, it should beappreciated that other appropriate programming languages and otherappropriate computer systems could also be used.

One or more portions of the computer system may be distributed acrossone or more computer systems coupled to a communications network. Forexample, as discussed above, a computer system that determines availablepower capacity may be located remotely from a system manager. Thesecomputer systems also may be general-purpose computer systems. Forexample, various aspects of the invention may be distributed among oneor more computer systems configured to provide a service (e.g., servers)to one or more client computers, or to perform an overall task as partof a distributed system. For example, various aspects of the inventionmay be performed on a client-server or multi-tier system that includescomponents distributed among one or more server systems that performvarious functions according to various embodiments of the invention.These components may be executable, intermediate (e.g., IL) orinterpreted (e.g., Java) code which communicate over a communicationnetwork (e.g., the Internet) using a communication protocol (e.g.,TCP/IP). For example, one or more database servers may be used to storedevice data, such as expected power draw, that is used in designinglayouts associated with embodiments of the present invention.

It should be appreciated that the invention is not limited to executingon any particular system or group of systems. In addition, it should beappreciated that the invention is not limited to any particulardistributed architecture, network, or communication protocol.

Various embodiments of the present invention may be programmed using anobject-oriented programming language, such as SmallTalk, Java, C++, Ada,or C# (C-Sharp). Other object-oriented programming languages may also beused. Alternatively, functional, scripting, and/or logical programminglanguages may be used. Various aspects of the invention may beimplemented in a non-programmed environment (e.g., documents created inHTML, XML or other format that, when viewed in a window of a browserprogram render aspects of a graphical-user interface (GUI) or performother functions). Various aspects of the invention may be implemented asprogrammed or non-programmed elements, or any combination thereof.

In embodiments of the present invention discussed above, results ofanalyses are described as being provided in real-time. As understood bythose skilled in the art, the use of the term real-time is not meant tosuggest that the results are available immediately, but rather, areavailable quickly giving a designer the ability to try a number ofdifferent designs over a short period of time, such as a matter ofminutes.

Having thus described several aspects of at least one embodiment of thisinvention in considerable detail with reference to certain preferredversion thereof, it is to be appreciated various alterations,modifications, and improvements will readily occur to those skilled inthe art. Such alterations, modifications, and improvements are intendedto be part of this disclosure, and are intended to be within the spiritand scope of the invention. Accordingly, the foregoing description anddrawings are by way of example only. Further, the phraseology andterminology used herein is for the purpose of descriptions and shouldnot be regarded as limiting. The use of “including,” “comprising,”“having,” “containing,” “involving,” and variations herein, are meant tobe open-ended, i.e., “including but not limited to.”

The invention claimed is:
 1. A power electronics system, comprising: an environmentally sealed electronics compartment for housing power electronics equipment; a plenum within the sealed electronics compartment for circulating air; a first liquid cooling loop configured to cool air flowing through the plenum; a second liquid cooling loop configured to directly cool the power electronics equipment, the second liquid cooling loop being fluidically separate from the first liquid cooling loop; and a controller for independently controlling airflow rates and coolant flow rates of the first liquid cooling loop and the second liquid cooling loop.
 2. The system of claim 1, wherein the power electronics equipment includes an inverter.
 3. The system of claim 1, wherein the first liquid cooling loop includes a plurality of heat exchangers and at least one fan for circulating air through the plenum.
 4. The system of claim 1, wherein the controller is programmed to analyze environmental data to control air and coolant flow rates of the first and second liquid cooling loops to maintain a pre-set temperature within the sealed electronics compartment.
 5. The system of claim 1, wherein the first liquid cooling loop includes a first heat exchanger, a second heat exchanger, and a pump to circulate a liquid coolant in the first liquid cooling loop.
 6. The system of claim 5, further comprising a fan to circulate air within the sealed electronics compartment, the fan being configured to draw air through the plenum and blowing air through the first heat exchanger.
 7. The system of claim 5, further comprising at least one fan to draw air from outside across the second heat exchanger to reduce a temperature of liquid coolant passing through the second heat exchanger.
 8. The system of claim 1, wherein the first liquid cooling loop includes a first heat exchanger and the second liquid cooling loop includes a second heat exchanger, and wherein the system further comprises at least one fan configured to draw air across the first heat exchanger and the second heat exchanger.
 9. The system of claim 1, wherein the plenum is configured to direct air across an upper portion or ceiling of the sealed electronics compartment and down an interior side wall of the sealed electronics compartment.
 10. The system of claim 1, wherein the second liquid cooling loop includes a heat exchanger and a pump to circulate liquid coolant in the second liquid cooling loop.
 11. The system of claim 10, wherein the second liquid cooling loop is configured to direct coolant through the power electronics equipment or through a device associated with the power electronics equipment.
 12. The system of claim 11, wherein coolant in the second liquid cooling loop is configured to flow through channels inside a thermal plate to which a power conversion bridge is mounted.
 13. The system of claim 11, wherein coolant in the second liquid cooling loop further is configured to flow through multiple thermal plates in contact with filter electronics and associated magnetic components.
 14. The system of claim 11, wherein coolant in the second liquid cooling loop is configured to flow adjacent to electronic switches.
 15. The system of claim 1, wherein the controller is configured to receive environmental data from environmental sensors to control the operation the first liquid cooling loop and the second liquid cooling loop.
 16. A method of thermal control in a power electronics system, comprising: controlling the flow rate of a first liquid cooling loop within a sealed electronics compartment for housing power electronics equipment; controlling the flow rate of a second liquid cooling loop configured to directly cool the power electronics equipment within the sealed electronics compartment, the second liquid cooling loop being fluidically separate from the first liquid cooling loop; and circulating air through a plenum provided within the sealed electronics compartment.
 17. The method of claim 16, further comprising circulating air within the sealed electronics compartment, drawing air through the plenum, and blowing air through a heat exchanger.
 18. The method of claim 16, wherein the first liquid cooling loop includes a plurality of heat exchangers and at least one fan for circulating air through the plenum.
 19. The method of claim 16, further comprising drawing air from outside the sealed electronics compartment, and directing air across a heat exchanger to reduce a temperature of liquid coolant passing through the heat exchanger.
 20. The method of claim 16, further comprising analyzing environmental data, and controlling flow rates of the first and second liquid cooling loops to maintain a pre-set temperature within the sealed electronics compartment.
 21. The method of claim 16, wherein the second liquid cooling loop is configured to direct coolant through the power electronics equipment or through a device associated with the power electronics equipment.
 22. The method of claim 21, wherein coolant in the second liquid cooling loop is configured to flow through channels inside a thermal plate to which a power conversion bridge is mounted.
 23. The method of claim 21, wherein coolant in the second liquid cooling loop further is configured to flow through multiple thermal plates in contact with filter electronics and associated magnetic components.
 24. The method of claim 21, wherein coolant in the second liquid cooling loop is configured to flow adjacent to electronic switches. 